In the production of energy, a particular production site, such as an offshore platform, may require the continuous monitoring of numerous variables in elements of the production unit, such as fluid pressure in production lines. Any one of such variables may, on a malfunction occurring in one of the elements, cause a shutdown of the entire system. Quick detection of the particular malfunction is desirable. The trial and error system is time consuming, and thereby is costly. This invention has as its prime goal the provision of a control system which may be used to monitor a number of variables in various elements, yet indicate the site of an initial malfunction.